Although progress has been made in describing a variety of secretory systems and some insights have been made regarding the regulatory mechanisms involved in exocytosis, the cellular control mechanisms and the actual molecular events involved in exocytosis are still poorly understood. Our recent research endeavors have been directed toward the development of new scientific information regarding the actual molecular events involved in rat salivary gland secretion. Our current hypothesis proposed that protein phosphorylation is one of the main cellular mechanisms for regulating rat submandibular mucin secretion. We are proposing to study certain aspects of rat submandibular mucin (mucous glycoprotein) secretion and once having gained further insight regarding the molecular events involved in rat submandibular mucin secretion, we plan to eventually study human tissue; salivary cells from normal patients and from patients with cystic fibrosis to see if a secretory defect is present in CF salivary cells. In particular, we are proposing to study the role of cAMP and cAMP mediated protein phosphorylation in the regulation of rat submandibular mucin secretion. We intend to: (1) purify and characterize two membrane bound phosphoproteins which we have identified as being phosphorylated in a beta-adrenergic receptor dependent manner, (2) purify and begin to characterize the protein components which comprise the "stimulus-coupled regulatory complex for exocytosis" which we propose is the actual enzymatic complex involved in regulating beta-adrenergic receptor mediated exocytosis in the rat submandibular gland, and (3) determine if other cellular proteins are being phosphorylated in a beta-adrenergic dependent manner. These studies are intended to provide new and basic scientific data regarding rat submandibular mucin secretion and should provide new insights into the actual molecular basis salivary gland secretion. These data are also important in expanding our understanding of normal oral health and disease.